Conventionally, in backlight units in liquid crystal display devices, a diffusion sheet (an optical sheet) that diffuses light from a light source is provided; furthermore, on that diffusion sheet, a lens sheet (an optical sheet) for enhancing light convergence is provided. As shown in FIG. 10, a diffusion sheet 146 and a lens sheet 147 are supported by a support portion (a support pin) sp of a lamp clip 1c that is fitted to a floor face 144B of a backlight chassis 144 (see Patent Document 1).
Incidentally, in such a backlight unit 149, a problem is caused by deformation of the resin-formed diffusion sheet 146 and the like due to heat from fluorescent tubes 142, in particular, deformation of the diffusion sheet 146 and the like dependent on heat or dissipated heat transmitted according to ON/OFF of the fluorescent tubes 142. The reason is that, when such deformation (bend) occurs, due to the bent diffusion sheet 146 and the like, a great force acts on the support portion sp of the lamp clip (a supporting unit) 1c. 
In the backlight unit 149 in Patent Document 1, however, the lamp clip 1c includes a buffer portion 105. The buffer portion 105 buffers the force acted on the support portion sp which is pressed down due to the bent of the diffusion sheet 146 and the like Thus, the support portion sp and the diffusion sheet 146 are not in relatively strong contact.
Patent Document 1: JP-A-2007-128887 (see FIG. 3 and paragraph 0036)